The application of recombinant DNA technology frequently involves the use of plasmids or cosmids in the cloning or manipulation of the target DNA. Typically, plasmids or cosmids are amplified by culturing micro-organisms harbouring plasmid or cosmid and ultimately extracting the plasmid or cosmid DNA from the culture. Purification of the extracted DNA is often required.
While automated or semi-automated procedures have been developed for some recombinant DNA techniques, particularly DNA purification and sequencing, many methods are still carried out manually. This is particularly the case for plasmid DNA extraction methods. Conventional methods, such as lysis by alkali or lysis by boiling (see Sambook et al., Molecular Cloning: A Laboratory Manual, 2nd Ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989) comprise a number of steps, the success of which rely on the skill of the worker. Repetitive application of such methods can thus lead to variation in the outcome of the procedures in the hands of an inexperienced worker.
It is often the case that plasmid or cosmid DNA must be extracted from a number of different cultures. Since micro-titre plates are used in some recombinant DNA techniques, it can be the case that extraction of DNA from hundreds of different cultures is desired. Conventional extraction procedures are not amenable to automation, or even semi-automation. Consequently, extraction of plasmid or cosmid DNA from a large number of individual cultures can constitute a time consuming and labour intensive operation.
There is therefore a need for a method which can be used to extract plasmid or cosmid DNA from cultures of micro-organisms which is simpler and more reproducible than existing procedures. There is also a need for an extraction method which is amenable to automation so that large numbers of cultures can be processed.
Similarly, the application of recombinant DNA technology and DNA analysis involves the use of genomic DNA from animal blood and other body fluids. Conventional methods such as extraction with organic solvents (see Sambook et al., Molecular Cloning: A Laboratory Manual, 2nd Ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y., 1989) comprise a number of steps, the success of which rely on the skill of the worker. Repetitive application of such methods can thus lead to variation in the outcome of the procedures in the hands of an inexperienced worker.
It is often the case that genomic DNA must be extracted from large numbers of samples. This is particularly the case for use of DNA in the polymerase chain reaction and DNA sequencing. Since microtitre plates are used in some recombinant DNA and genetic analysis techniques, it can be the case that DNA from hundreds of samples is required.
There is therefore a need for a method which can be used to extract genomic DNA from blood and other body fluids which is simpler and more reproducible than existing procedures. There is also a need for an extraction method which is amenable to automation so that large numbers of samples can be processed.